Genetic diversity and structure of the Military Macaw (Ara militaris) in Mexico: Implications for conservation

Abstract

The Military Macaw (Ara militaris) is a globally threatened species with a fragmented distribution, and assessing the genetics of populations could help identify conservation units. Nine microsatellites were used to analyze 86 samples in seven localities along the Sierra Madre Occidental, the Sierra Madre del Sur, and the Sierra Madre Oriental in Mexico. Results showed that the Military Macaw has moderate levels of genetic diversity, similar to that found in other macaw species in Latin America. This species shows a high genetic structure; we find a genetic break between localities separated by the Central Plateau and the Trans-Mexican Volcanic Belt, which serve as geographic barriers. However, the locations within each genetic group are not genetically differentiated. It was observed that three locations of the Military Macaw have excess homozygotes, which could indicate a small effective size of the population and in combination with genetic isolation could increase the risk of extinction of the species. We propose two genetic groups for the species, the first comprising localities in the Sierra Madre Occidental and the Sierra Madre del Sur, and the second comprising localities of the Sierra Madre Oriental. According to the genetic differentiation, which was significant between the physiographic regions, and the unique allelic richness shown in this study, these two groups should be considered as independent conservation units. We strongly recommend the conservation and restoration of the natural habitats of the Military Macaw to maintain and increase the size of its population and recover and expand its original geographical distribution.